A water-based ink composition useful for ink jet recording usually comprises dyes, organic solvents and water. In order to obtain good ink jet recording, the ink composition is required to meet various needs.
For example, physical properties of the ink composition such as viscosity, surface tension, specific electric conductivity, density and pH are to be adequately controlled within a desired range so as to apply the composition for any means of generating ink droplets and controlling the flying direction of the ink droplets.
Moreover, these physical properties are required to be kept unchangeable for a long period of time. For example, the ink composition must not produce precipitates due to chemical changes or the like during extended storage or use or at the rest time of recording operation. When produced, the precipitates easily clog a jet nozzle of an ink jet recording apparatus which has a diameter as small as 10-60 .mu.m. This interrupts the jetting of ink droplets. Even when the composition produces no precipitate, but solid or cohesive matters, they easily adhere to the nozzle which adversely affects the recording ability, jetting stability, and jetting response.
Further, high heat resistance is also required particularly for a thermal energy-utilizing ink jet system which has been developed recently.
In addition, it is desired that recorded images are sufficiently high in the degree of contrast and clearness and excellent in water resistance and light fastness.
As dyes for ink jet recording, heretofore, direct, acid and reactive dyes have been used. For example, C. I. Direct Black 17, 19, 22, 32, 51, 56, 62, 71, 74, 75, 77, 94, 105, 106, 107, 108, 112, 113, 117, 118, 122, 132, 133, 146, 154, 159, 162, 168, 169 and 173; C. I. Direct Blue 86, 87 and 199; C. I. Direct Red 9; C. I. Direct Yellow 86, 142 and 144; C. I. Acid Yellow 23, 42 and 49; C. I.. Acid Red 14, 34, 35, 37 and 249; C. I. Acid Blue 7, 9 and 249; C. I. Reactive Red 24, 35, 111, 114, 174, 180 and 184; C. I. Food Black 2, etc. are illustrated.
In the Japanese Patent (Laid-Open) Publication No. 123,866/1989, azo dyes having a substituent group of --SO.sub.2 CH.sub.2 CH.sub.2 OH or --SO.sub.2 CH.dbd.CH.sub.2 have been used for ink jet recording inks.
However, use in an red dyes heretofore used are not yet satisfactory for the ink jet recording ink.
The present inventors have undertaken extensive studies to find ink compositions meeting the needs described above and useful for ink jet recording, and as a result have attained the present invention.